User interfaces may have elements that vary in size. For example, a user interface element can be a button that a user selects to perform an action. The elements may each include a background image that has content, such as text, drawn on the background image. For example, the button may have a blue background image and text that indicates the user should select the button to save a file.
An element of a first size can use a background image of a corresponding first size, and an element of a second size can use different background image that corresponds to the second size. A user interface may use both of these images if displaying two different sized elements even if the images are substantially the same. For example, both images may include a solid green color, but the user interface uses two images of different sizes because the elements displayed are different sizes.